Along with the miniaturization of components and quick development of the process of manufacturing semiconductors to submicron level, the component density of silicon chips per unit area increases dramatically such that the reduced dimension interconnects between the components induces higher electric resistance and the narrow line widths increase the parasitic capacitance thereby resulting in signal delays. An optimum measure of reducing the signal delays is to employ dielectric materials with a low dielectric constant and replace the conventional aluminum interconnects with copper of better electrical conductivity. However, the fabrication of copper interconnects has resulted in significant impacts in the process of packaging due to the entirely different mechanisms involved in the oxidization of copper and aluminum metals. For aluminum, a self-passivation is easily formed on its surface to prevent further oxidation of the aluminum underneath the self-passivation layer, where the aluminum oxide film is scrubbed off by ultrasonic power during thermosonic wire bonding so as to ensure bonding between the metal wires and the aluminum pads. Copper, on the contrary, is easily oxidized under the atmosphere while the copper oxide film does not provide a self-passivation effect as the aluminum oxide film does. Not only does such a characteristic become a bottleneck in the thermosonic wire bonding process adopted in the packaging of semiconductors, it adversely affects the mechanical and physical properties of copper pads. The packaging process employed by electronic components generally includes the process of die sawing, die bonding, wire bonding and encapsulation. During die sawing, the wafer surface is cleaned by deionized water to remove the heat applied to the wafer and to carry away the silicon debris generated during the sawing process. The wafer is then placed in a cleaning and drying machine after die sawing to be further cleansed by deionized water to remove the debris remained on the wafer surface, and then dried. The dried wafer is then adhered to a leadframe by silver thermal adhesive and placed in curing oven to be cured for 0.5 to 1.5 hours at a temperature ranging from 150° C. to 175° C. thereby curing the silver thermal adhesive. During die sawing and die bonding, the wafer is exposed to moisture and atmosphere and is subjected to a high temperature so as to cause considerable oxidization on the surface of copper pads. Further, during the thermosonic wire bonding of copper pads, a proper operation temperature of the thermosonic wire bonder ranges from 120° C. to 220° C. Chips with copper pads, under such an elevated temperature and atmospheric surrounding, may be protected by inert gases or subjected to a high vacuum environment to prevent from oxide film formation on the surfaces of the copper pads. Since it is relatively difficult to realize a vacuum environment in the thermosonic wire bonding process during mass production, it is thus essential for the packaging of chips with copper pads to overcome the problems caused by the copper pad oxidation.